Understand my husband is the real brains of the AP stuff, but I'll do my best.
Tilapia are gill feeders, you WANT the algae to grow in their tank, so no copper or silver for them. Other fish... I am not sure you would not screw up the nitrite / nitrate conversion - it is a bacteria that makes the conversion, so my instinct is no copper or silver in the system at all.
Vitamins and minerals or rock dust will all add to the TDS, and that affects the pH, so you may find you "fix"something that was not broke and then break something that wasn't. If you see evidence of imbalance in the system, a temporary addition of something corrective makes sense, but in the long run you want to fix the imbalance. Most issues respond to tweaking the system - more oxygen in the water, warmer or cooler water, more grow beds or more fish.
If you really want to add minerals, I would consider something like "Redmond minerals" - the stuff that I feed my cows sounds kinda tasty... lol! OK, sounds healthy, not tasty. Anyway, I'd sprinkle a bit of it in the first grow bed out of the system, so it gets time to be absorbed by as many plants as possible before returning to the fish tank, but I'd watch the pH like a hawk.
This is the article that got my posting privileges revoked: